Home | Projects | Street and Roadway Improvements
Representative highlights of Willdan Geotechnical's recent road projects are presented below.
Client: County of Ventura, California
Project: Balcom Canyon Road Failure
The project consisted of an engineering geology and geotechnical engineering investigation of distress to Balcom Canyon Road between South Mountain and Bradley Roads. The investigation included field mapping, development of temporary bulldozer roads for drill rig and backhoe access. Fieldwork also included excavation, sampling and detailed geologic logging of 24 backhoe test pits, excavation, sampling and downhole logging of 18 bucket auger borings. Geotechnical laboratory testing was conducted, and deep-seated slope stability analyses were performed. Cross sections were developed, and recommendations for repair of the roadway and partial stabilization of the landslides were provided.
Client: City of La Cañada Flintridge, California
Project: Alta Canyada Road Distress
Willdan Geotechnical performed geotechnical investigation of distress to Alta Canyada road due to the failure of an adjacent slope. The fieldwork included geologic mapping of slopes below the road surface, drilling, soil sampling, preparation of a geologic cross section, computerized slope stability analyses to determine the deep-seated factor of safety of the road surface and recommendations for stabilization.
Client: Santa Clarita, California
Project: Old Road Widening and Drainage Improvement
This project addressed geotechnical issues including subsurface exploration, liquefaction potential, settlement analysis, slope stability, geologic bedding, embankment excavation, construction dewatering, soil erosion, pavement design, and Caltrans Standards related to new roadway and flood control facilities.
Scope of services provided by Willdan Geotechnical included
- Review of existing reports and literatures related to the project site;
- Application of encroachment permits for drilling and other subsurface exploration tasks; i.e., pothole excavation, and underground utility clearance;
- Subsurface exploration included hollow-stem and Cone Penetration Tests;
- Subsurface exploration using an all-terrain drill rig on a berm;
- Collect bulk and Modified California Samples;
- Preparation of borings logs in accordance with Caltrans format;
- Laboratory testing
- Geotechnical Cross-section preparation; and
- Report preparation.
The Old Road widening project will required coordination with several agencies as well as several on-going projects in the area. The list of the agencies include:
- Los Angeles County Public Work
- City of Santa Clarita
- MTA
- Caltrans
- Army Corps of Engineers
- U.S. Department of Fish and Games
Willdan Geotechnical has established cordial working relationship with these agencies during encroachment permit applications and report review process.
The technical aspect of this projects included:
- Liquefaction potential of the subgrade soils under the storm drains pipe
- Stability of the backcut due to unfavorable geologic beddings during excavation of the storm drain pipes
- Differential settlement along the storm drain pipes
- Settlement of existing utilities under new embankment fill
- Static and Seismic stability of roadway embankment
- Construction dewatering
The report was reviewed and approved by the Los Angles County Department of Public work.
Willdan Geotechnical is currently working on the proposed Santa Clara River bank erosion protection project as part of the Old Road Widening project. The project will require geotechnical input for a new bike trail, temporary excavation for rip-rap blanket construction on the new Santa Clara River Bridge abutments, and the construction of 1,500 feet of soil cement blanket on the “Old Road Widening” riverbank. The proposed soil cement blanket require excavation of approximately 20 feet below the existing river bed. The project also requires input for the construction of a double-box culvert along an existing unlined channel as well as converting a single-box culvert to a double-box culvert.